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)(11,20)(12,24)(13,18)(14,17)(15,22)(16,27)(19,28)(21,34)(23,33)(25,31)(26,36)(29,32)(30,35)(37,39)(38,40) involution — undirected(2,6)(7,8)(9,11,13,22)(10,15,18,20)(12,25,26,39)(14,29,28,23)(16,34,35,40)(17,33,19,32)(21,27,38,30)(24,37,36,31)(9,12)(10,16)(11,21)(13,26)(14,30)(15,31)(17,24)(18,35)(19,36)(20,37)(22,38)(23,25)(27,28)(29,39)(32,40)(33,34) involution — undirected(1,3,5,4)(2,7,6,8)(10,17)(14,28)(15,32)(16,24)(18,19)(20,33)(23,29)(25,39)(27,30)(31,40)(34,37)(35,36)(1,4,5,3)(2,7,6,8)(10,18)(15,20)(16,35)(17,19)(24,36)(31,37)(32,33)(34,40)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.