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