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