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