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