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