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