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