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