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