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