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