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