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