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