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