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