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