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