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