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