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