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