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