One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,5,3)(4,7,8,6)(9,10,14,16)(11,15,19,23)(12,17,20,22)(13,18,21,24)(25,26,30,33)(27,31,37,40)(28,32,38,29)(34,35,36,39)(2,3)(6,7)(9,11)(10,15)(12,13)(14,19)(16,23)(17,18)(20,21)(22,24)(25,27)(26,31)(28,36)(29,35)(30,37)(32,39)(33,40)(34,38) involution — undirected(2,3)(4,8)(10,16)(11,19)(13,21)(17,22)(25,28,30,38)(26,32,33,29)(27,34,37,36)(31,35,40,39)(2,3)(6,7)(9,12)(10,17)(11,13)(14,20)(15,18)(16,22)(19,21)(23,24)(25,29)(26,28)(27,35)(30,32)(31,36)(33,38)(34,40)(37,39) involution — undirected(1,3,5,2)(4,7,8,6)(9,13)(10,18)(11,20)(12,19)(14,21)(15,22)(16,24)(17,23)(25,28)(26,32)(27,36)(29,33)(30,38)(31,39)(34,37)(35,40)(1,4,5,8)(2,6,3,7)(9,10)(11,15)(12,17)(13,18)(14,16)(19,23)(20,22)(21,24)(25,27)(26,31)(28,36)(29,35)(30,37)(32,39)(33,40)(34,38)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.