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