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