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