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