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