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