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