One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,5,8)(3,6,4,7)(9,10)(11,15)(12,17)(13,18)(14,16)(19,22)(20,23)(21,24)(25,26,30,33)(27,34,35,31)(28,29,32,39)(36,37,38,40)(1,2)(3,6)(4,7)(5,8)(9,11,14,13)(10,15,16,18)(12,19,20,21)(17,22,23,24)(25,27)(26,31)(28,38)(29,37)(30,35)(32,36)(33,34)(39,40)(10,16)(15,18)(17,23)(22,24)(27,35)(31,34)(36,38)(37,40) involution — undirected(9,12)(10,17)(11,19)(13,21)(14,20)(15,22)(16,23)(18,24)(25,28)(26,29)(27,36)(30,32)(31,40)(33,39)(34,37)(35,38) involution — undirected(1,3,5,4)(2,6,8,7)(9,13,14,11)(10,18,16,15)(12,19,20,21)(17,22,23,24)(25,27)(26,31)(28,38)(29,37)(30,35)(32,36)(33,34)(39,40)(1,4,5,3)(2,7,8,6)(9,10)(11,15)(12,17)(13,18)(14,16)(19,22)(20,23)(21,24)(25,29)(26,32)(27,37)(28,33)(30,39)(31,36)(34,38)(35,40)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.