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