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