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