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