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