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