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