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