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