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