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